On 9/28/23 2:12 AM, Andrii Nakryiko wrote:
On Mon, Sep 25, 2023 at 10:59 PM Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote:
[...]
+struct bpf_link *
+bpf_program__attach_meta(const struct bpf_program *prog, int ifindex,
+ bool peer_device, const struct bpf_meta_opts *opts)
you mentioned that there are plans to also support cases where there
is no primary-peer. Is that going to be a primary-only setup or will
it be some third option? If the latter, should this `bool peer_device`
be an enum then?
Agree, enum is more flexible either way, will change it to that.
+{
+ LIBBPF_OPTS(bpf_link_create_opts, link_create_opts);
+ enum bpf_attach_type attach_type;
+ __u32 relative_id;
+ int relative_fd;
+
+ if (!OPTS_VALID(opts, bpf_meta_opts))
+ return libbpf_err_ptr(-EINVAL);
+
+ relative_id = OPTS_GET(opts, relative_id, 0);
+ relative_fd = OPTS_GET(opts, relative_fd, 0);
+ attach_type = peer_device ? BPF_META_PEER : BPF_META_PRIMARY;
+
+ /* validate we don't have unexpected combinations of non-zero fields */
+ if (!ifindex) {
+ pr_warn("prog '%s': target netdevice ifindex cannot be zero\n",
+ prog->name);
+ return libbpf_err_ptr(-EINVAL);
+ }
+ if (relative_fd && relative_id) {
+ pr_warn("prog '%s': relative_fd and relative_id cannot be set at the same time\n",
+ prog->name);
+ return libbpf_err_ptr(-EINVAL);
+ }
+
+ link_create_opts.meta.expected_revision = OPTS_GET(opts, expected_revision, 0);
+ link_create_opts.meta.relative_fd = relative_fd;
+ link_create_opts.meta.relative_id = relative_id;
+ link_create_opts.flags = OPTS_GET(opts, flags, 0);
+
+ return bpf_program_attach_fd_type(prog, ifindex, "meta", attach_type,
+ &link_create_opts);
+}
+
struct bpf_link *bpf_program__attach_freplace(const struct bpf_program *prog,
int target_fd,
const char *attach_func_name)
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 0e52621cba43..827d29cf9a06 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -800,6 +800,21 @@ LIBBPF_API struct bpf_link *
bpf_program__attach_tcx(const struct bpf_program *prog, int ifindex,
const struct bpf_tcx_opts *opts);
+struct bpf_meta_opts {
+ /* size of this struct, for forward/backward compatibility */
+ size_t sz;
+ __u32 flags;
+ __u32 relative_fd;
+ __u32 relative_id;
+ __u64 expected_revision;
nit: move flags to be the last, so we don't have that padding before
expected_revision?
Sounds good, will do.
+ size_t :0;
+};
+#define bpf_meta_opts__last_field expected_revision
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_meta(const struct bpf_program *prog, int ifindex,
+ bool peer_device, const struct bpf_meta_opts *opts);
+
struct bpf_map;
LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 57712321490f..2dd4fe2cba3d 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -397,6 +397,7 @@ LIBBPF_1.3.0 {
bpf_obj_pin_opts;
bpf_object__unpin;
bpf_prog_detach_opts;
+ bpf_program__attach_meta;
bpf_program__attach_netfilter;
bpf_program__attach_tcx;
bpf_program__attach_uprobe_multi;
--
2.34.1
